Are Black Phosphorus Hydrogels Antimicrobial Without Photonic Activation?
Leon D Pope1, Shreehari Kodakkat2, Aaron Elbourne2
1School of Engineering, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia.
Molecules (Basel, Switzerland)
|June 13, 2025
Summary
Black phosphorus (BP) nanoflakes show significant antimicrobial activity against Staphylococcus aureus in hydrogels without light activation. However, the hydrogel may limit BP
Area of Science:
- Biomaterials Science
- Nanotechnology
- Antimicrobial Materials
Background:
- Black phosphorus (BP) nanoflakes are explored for antimicrobial wound healing and implant infections, offering antibiotic-free bactericidal properties.
- Hydrogels serve as delivery systems for BP, but typically require photonic activation (e.g., near-infrared laser) for reactive oxygen species (ROS) generation and photothermal effects.
- Photonic activation poses challenges for implant-coating applications, particularly with porous orthopedic implants.
Purpose of the Study:
- To evaluate the antimicrobial efficacy of black phosphorus (BP) nanoflakes within Pluronic F127 (F127) hydrogels against Staphylococcus aureus.
- To determine if BP nanoflakes retain antimicrobial activity without photonic activation (e.g., NIR laser stimulation) in a hydrogel matrix.
Main Methods:
- Black phosphorus (BP) nanoflakes were suspended in Pluronic F127 (F127) hydrogels.
- The antimicrobial effectiveness of the BP-loaded hydrogel against Staphylococcus aureus was assessed via passive diffusion.
- Bacterial inhibition percentages were quantified at a specific BP concentration (5120 µg/mL).
Main Results:
- BP nanoflakes in F127 hydrogels achieved 89.4 ± 7.6% bacterial inhibition against Staphylococcus aureus via passive diffusion.
- Complete bacterial eradication was not achieved, suggesting limitations in the hydrogel system's antimicrobial delivery.
- The F127 hydrogel interface may act as a barrier, hindering bacterial contact with the antimicrobial BP and contributing to its degradation.
Conclusions:
- Black phosphorus nanoflakes exhibit passive antimicrobial activity in Pluronic F127 hydrogels against Staphylococcus aureus.
- The hydrogel matrix may impede the full bactericidal potential of BP, necessitating further investigation into optimized delivery systems.
- These findings suggest potential for antibiotic-free antimicrobial coatings but highlight the need to overcome delivery system limitations.
